Systems and methods for ozone water generator

ABSTRACT

A novel cell for generating ozonated water, the cell comprises a nafion membrane separating a diamond coated anode, and a gold surfaced cathode enclosed within a cell housing with the catalyst side of the nafion membrane facing the cathode. The cell housing has a cathode housing portion and an anode housing portion separated by the membrane, each housing portion having ridges to enhance substantially even flow of fluid over the cathode and anode. The housing portions contain O-rings in grooves to prevent leaks, and alignment features to keep the electrodes aligned. The cathode and anode have an array of holes allowing fluid to penetrate to the surface of the niobium membrane. Input ports allow fluid to flow into the housing and over the anode and cathode and then out of the housing through outlet ports. The housing may also incorporate an integrated spectral photometer including a bubble trap.

RELATED APPLICATION

This application is a continuation of copending U.S. application Ser.No. 17/042,002 filed on Sep. 25, 2020 which is a 371 of internationalapplication PCT/US2019/024758 filed on Mar. 29, 2019 and claims priorityto provisional application No. 62/649,928 filed Mar. 29, 2018 which arehereby incorporated herein by reference.

FIELD

The field relates to liquid ozone generating systems, and moreparticularly to a system for efficient, controlled generation ofozonated water.

BACKGROUND

Liquid oxidants such as ozonated water are widely used for cleaning andsterilization including water treatment, equipment sterilization, andfood sterilization. Ozone is a strong oxidizer because its third oxygenatom can easily detach and bond with (i.e., oxidize) contaminants.Recent changes in sterile drug processing standards permit such a liquidphase ozone sterilant to be used as an alternative to heat andradiation. These cleaning and sterilization processes often require acontrolled level of ozone concentration.

Known method of generating ozonated water use direct electrolysiswherein feed water is brought into direct contact with the electrolyticsurface of a catalytic electrode to be electrolyzed into ozonated water.The catalytic electrode can include a cation exchange membrane, and ananode and a cathode in pressure contact with the cation exchangemembrane on the respective surfaces. A feed-water supply path supplieswater which comes into contact with the anode and the cation exchangemembrane and the resulting ozonated water is then discharged through anozonated water discharge path. These cleaning and sterilizationprocesses often require a controlled level of ozone concentration.

These known devices for generating ozonated water are inefficient,inconsistent in performance and ozone concentration, often leak, and areexpensive to fabricate and maintain. Thus, an improved ozonated watergenerator is needed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example water ozonator cell, accordingto an example embodiment.

FIG. 2A is a an exploded view of an example ozonator cell device,according to an example embodiment;

FIG. 2B is a side view of the example ozonator cell of FIG. 2A.

FIG. 2C is a cross-sectional view of the example of FIG. 2A.

FIG. 3 is a functional diagram of an example system utilizing anozonator cell.

FIG. 4 is a functional block diagram of an example embodiment of controlcircuitry for the system of FIG. 3 .

FIG. 5 is a block diagram of an example computer system within which aset of instructions for causing the machine to perform any one or moreof the methodologies discussed herein may be executed or stored.

DETAILED DESCRIPTION

Example apparatus and methods for controlled ozonation of water aredescribed herein. In the following detailed description of exampleembodiments of the invention, reference is made to the accompanyingdrawings that form a part hereof, and in which is shown by way ofillustration specific example embodiments in which the invention may bepracticed. These embodiments are described in sufficient detail toenable those skilled in the art to practice the inventive subjectmatter, and it is to be understood that other embodiments may beutilized and that logical, mechanical, electrical and other changes maybe made without departing from the scope of the inventive subjectmatter.

Some portions of the detailed descriptions which follow are presented interms of algorithms and symbolic representations of operations on databits within a computer memory. These algorithmic descriptions andrepresentations are the ways used by those skilled in the computer artsto most effectively convey the substance of their work to others skilledin the art. An algorithm is here, and generally, conceived to be aself-consistent sequence of steps leading to a desired result. The stepsare those requiring physical manipulations of physical quantities.Usually, though not necessarily, these quantities take the form ofelectrical or magnetic signals capable of being stored, transferred,combined, compared, and otherwise manipulated. It has proven convenientat times, principally for reasons of common usage, to refer to thesesignals as bits, values, elements, symbols, characters, terms, numbers,or the like. It should be borne in mind, however, that all of these andsimilar terms are to be associated with the appropriate physicalquantities and are merely convenient labels applied to these quantities.Unless specifically stated otherwise as apparent from the followingdiscussions, terms such as “processing” or “computing” or “calculating”or “determining” or “displaying” or the like, refer to the action andprocesses of a computer system, or similar computing device, thatmanipulates and transforms data represented as physical (e.g.,electronic) quantities within the computer system's registers andmemories into other data similarly represented as physical quantitieswithin the computer system memories or registers or other suchinformation storage, transmission or display devices.

In the Figures, the same reference number may be used to refer to anidentical component that appears in multiple Figures. Signals andconnections may be referred to by the same reference number or label,and the actual meaning will be clear from its use in the context of thedescription.

The description of the various embodiments is to be construed asexamples only and does not describe every possible instance of theinventive subject matter. Numerous alternatives could be implemented,using combinations of current or future technologies, which would stillfall within the scope of the claims. The following detailed descriptionis, therefore, not to be taken in a limiting sense, and the scope of theinventive subject matter is defined only by the appended claims.

FIG. 1 is a block diagram of an example water ozonation cell 100. Thecell 100 is an example in which a cathode 102 (e.g., stainless steel) isseparated by a polymer membrane 104 (e.g. a nafion membrane) from ananode 106 (e.g. diamond plated niobium) as shown. In operation the cell100 separates water into Hydrogen (H₂), and into oxygen in the form ofO₂ and Ozone (O₃) by direct electrolysis using the polymer membrane 104.In this process, water is separated and independently introduced to theanode side of the electrolysis cell and to the cathode side of the cell.Water introduced in the anode side is electrolytically decomposed, aportion is converted to ozone, and mixes into the remaining water,thereby building the O₃ concentration in the water on the anode side. Onthe cathode side, the H₂ that has been separated and conveyed throughthe membrane is released into the water.

Advantages to producing ozone with such an electrolytic system are: 1)there is no ionic contamination because the feed-water is beingdisassociated using a solid hydrated ion exchange membrane; 2) theprocess water used for disinfection is the source of the oxygen for thegeneration of ozone—consequently, no outside contamination is introducedinto the system being treated; and 3) the ozone is dissolved in theprocess water as soon as it is formed with no residual contaminants.

In the direct water electrolysis cell 100 of FIG. 1 , ozone gas evolvesat a voltage higher than 1.511 V, accompanied by oxygen evolution. Byincreasing voltage to above 2.075V, the oxidation of O₂ gas to form O₃is also expected. Since O₂ evolution occurs at a lower potential than O₃evolution, the production rate and electric power consumption in O₂evolution are much higher than those in O₃ evolution. To ensure,therefore, that as much ozone as possible is produced, the anode shouldhave an over potential above the decomposition and ozone reactionpotential and the catalytic layer should inhibit the formation ofdiatomic oxygen and encourage the formation of ozone. This electrolysiscell design provides an efficient method of O₃ generation when theproper operating parameters are met. Parametric feedback may be utilizedto ensure proper levels of ozone are produced in a given cell 100. Acell powered with a constant current source will have a resultant DCvoltage which is in direct relation to ozone production and thus can becontrolled to provide a consistent concentration of ozone. In someembodiments a desired concentration of 16 ppm of ozone can be achieved.

The cell's current density relationship to ozone generation is a factorof surface area and applied current. The current efficiency, andtherefore ozone production, is stable at controlled water temperatures.In some embodiments a desired temperature between about 17° C. and 20°C. will provide a stable ozone concentration where the decay rate ismatched by the generation rate. In the case of the cell 100, theconstant flow rate of water, the maximum water temperature and thegeneration time will be factors in the stabilized ozone productionconcentration.

In conjunction with current and voltage, there are several other factorswhich affect ozone production. The factors are 1) fluid flow through thecell, 2) time of generation, 3) water pH and purification, 4) totalwater volume, and 5) water temperature. The cell 100 permits monitoringand regulating the above-mentioned five factors at a steady-state so asto significantly diminish the variable effects on ozone production. Thefluid flow may be monitored and regulated to ensure it maintains aconstant flow rate. The time of cell operation to generate ozone may beset to a defined duration. The water input is preferably USP sterilewater which controls the pH and eliminates any contaminants. The inputwater volume may be monitored and controlled to ensure repeatable levelsare sustained during the ozone generation cycle. The water temperaturemay be monitored and regulated to ensure it does not exceed apredetermined threshold.

FIG. 2A illustrates an exploded view of an embodiment of a novelozonation cell 200 which is a specific example embodiment of the cell100 of FIG. 1 . The cell 200 comprises an anode 202 having a diamondcoating on the side 203 facing a cathode 204 separated by a membrane206. In the illustrated embodiment of FIG. 2A, both the anode 202 andthe cathode 204 have an array of small holes 201, 205 that extendthrough the electrodes 202, 204. In one embodiment the anode 202 may becomposed, for example, of niobium plated with a thin layer of dopeddiamond and the cathode 204 may be composed, for example, of stainlesssteel plated with gold.

The anode 202 may be any suitable conductor and is preferably niobium(or some other suitable material) coated with a layer of doped diamond.In one embodiment the niobium is about 99% pure and the diamond layer isabout 2 microns thick. An array of holes 201 in the anode 202 allowswater to contact the membrane 206 on the anode side while porosity ofthe membrane 206 allows the water to spread out between the holes of thearray to wet the surface of the membrane 206 between the holes. Thearray of holes 201 of the anode 202 in one embodiment covers at least75% of the surface area of the anode exposed to water (i.e., the areawithin the O-ring 214). In one embodiment the holes 201 are about 70thousandths of an inch in diameter and should be large enough to allowwater to adequately contact the membrane 206.

In some embodiments, the niobium anode surface is first anodized tocreate pores to promote surface adhesion, and then the doped diamondplating is applied. In other embodiments, the niobium surface may bebead blasted first and then etched to create an optimal surface textureto increase surface adhesion of the diamond plating In other approach,sputtering niobium onto the base material using a mask may be used tocreate surface texture to improve adhesion. In yet another embodimentthe anode may be made of a thin mesh of niobium to maximize surfacearea, the mesh anode surface may then be prepared by any suitable methodsuch as those described above which is then coated with a doped diamondlayer. The diamond layer of the anode is preferably doped (i.e., dopedwith boron) to a concentration sufficient to make the diamond layerconductive. The diamond layer in some embodiments may be approximatelytwo microns thick.

The cathode 204 is composed of a suitable conductor (e.g., stainlesssteel, gold, silver, etc.) which does not interact excessively with thefluid, preferably a gold surfaced electrode. In some embodiments thecathode 204 may be stainless steel plated on both sides with gold tocreate a gold surface to eliminate interaction of the water with iron.The cathode 204 also includes the array of holes 205 as shown. The array205 in some embodiments covers at least 75% of the surface area of thecathode which is exposed to water (i.e., the area enclosed within theO-ring 212). The holes allow water to contact the membrane 206 on thecathode side while porosity of the membrane 206 allows the water tospread out between the holes to wet the full surface covered by thearray of holes 205 between the holes. In one embodiment the holes 205are approximately 70 thousandths of one inch in diameter.

In the illustrated embodiment, the cathode 204 and anode 202 areseparated by a polymer membrane 206, for example a nafion membrane. Themembrane may contain a conductive diffuser oriented with the diffuserside 208 facing the cathode, as shown. The membrane may also contain aplatinum catalyst on the side facing the cathode. In the illustratedembodiment an O-ring 212 (e.g. silicone) is located between the cathode204 and a body element 210 to form a seal therewith, and a second O-ring214 is located between the anode 202 and a second cell body element 216to form a seal to minimize leakage of water from around the edge of theelectrodes 204 and 206. In one embodiment, the membrane 206 is about 10thousandths of an inch thick. The membrane 206 may absorb water so adouble sided adhesive border 209 may be adhered to the membrane 206 toenhance the seal around the edges. A groove 211 may be formed in eachbody element 210, 216 to receive the O-rings.

In one embodiment, the body elements 210, 216 may be composed of ozoneresistant high density polyethylene or CPVC. Four bolts 220-223 togetherwith nuts 224-227 and washers 228, 229 hold the body elements 210, 216together to form an enclosure while holding the cathode 204, anode 202and membrane 206 in place and properly aligned within the enclosure.Water inlet/outlet ports 230, 232 allow entry and exit of water to andfrom the cell 200. Water inlet/outlet adaptors 240, 242 are mounted tothe ports 230, 232 to allow connection of water tubing. Ridges 250 maybe formed in the inner surface of each body element 210, 216 to enhancethe water flow pattern so that the water passes relatively evenly acrossthe full face of the anode 203 and cathode 204 as it passes through thecell.

FIG. 2B illustrates an end view of the ozonation cell 200 with the bolts220-223 and inlet/outlet adaptors 240, 242. FIG. 2C illustrate across-sectional view of the cell 200 along the line AA of FIG. 2Bshowing the body elements 210, 216 held together by the bolts 222, 223.Shown between the two body element 210, 216 are the O-ring 212, 214, themembrane 206, the cathode 204 and the anode 202. In some embodiments thebolts 220-223 are torqued to a desired level to control pressure on theelectrodes. In one embodiment the bolts are torqued to approximately 6ft-lbs to provide sufficient tightness while allowing water to flow onboth sides contacting the nafion membrane 206 and to allow current topass through the cell.

During operation of the cell 200, dc voltage is applied across the cellwith the negative applied to the cathode and positive side to the anode.Water is pumped through the cell 200 entering the cathode side throughthe inlet port 232 to flow across the face of the cathode 204 and out ofthe cell 200 through the outlet port 230. The water is supplied viatubing connected to the outlet adapter 240, and flows out via tubingconnected to the outlet adaptor 242. Similarly water enters the anodeside of the cell 200 through the inlet port 215, from tubing connectedto the inlet adapter 243, flows across the face of the anode 202 and outof the cell 200 via the outlet port and outlet adaptor 241. The waterflowing on each side contacts the membrane 206 through the holes 201,205. The water flow rate, water temperature, cell voltage and currentare monitored and controlled to control the ozone concentration out ofthe cell 200.

In an alternative embodiment, the ozonation cell may include an integralspectral photometer to allow monitoring and control of ozoneconcentration. The spectral photometer portion projects UV light throughthe water flowing through a transparent chamber to measure ozoneconcentration. The integral spectral photometer also incorporates abubble trap.

FIG. 3 illustrates a functional diagram of an embodiment of an examplewater ozonation system 300, according to an example embodiment. Thesystem 300 as shown includes an ozonation cell 200 having a cathode side304, an anode side 302, and the membrane 206. The cell 200 is coupled toa pair of water reservoirs 306, 308 as shown. The reservoirs 306, 308may be sized as needed, for example, in one embodiment, holding 50 mland 200 ml, respectively. Fluid flows through the cell 200 via a cathodepath 310 and an anode path 312. The fluid is driven through the cathodepath 310 by a pump 314 which returns fluid with hydrogen to the hydrogenside reservoir 306 via a tubing path 318 through a three way valve 320which can direct fluid into an excess fluid receptacle 322, as shown, toflush excess fluid. The fluid is pumped through the anode path 312 by apump 316 via a tubing path 324 to the ozone reservoir 308 through athree way valve 326 which can also direct fluid to the reservoir 306 viaa path 328, as shown. Also, in the illustrated embodiment, fluid canalso be channeled from the bottom of the reservoir 308 via path 330through a three way valve 332 to the top of the reservoir 308. A sourceof fluid is provided from a reservoir 334 to the reservoir 308 via apath 336. The reservoir 334 may be sized to hold a suitable amount forfluid, for example, in one embodiment, 250 ml of water. Levels in thereservoirs 306, 308 are monitored by level sensors 340, 342 and fluidtemperature in the ozone reservoir 308 is monitored using temperaturesensor 344. A cooler 350 (e.g. a Peltier cooler) permits control offluid temperature in the reservoirs 308. A vent 352 provides a path forventing of excess gas from the reservoirs 306, 308.

Water from the ozone reservoir 308 is circulated to maintain a desiredozone level in the water while water is drawn out to be used forsterilization. The ozone concentration is controlled by controlling thevoltage across the cell 200 and the current through the cell 200. Acontrol board 400 (see FIG. 4 ) can monitor the cell 200 current andvoltage and fluid temperatures to control ozone generation.

FIG. 4 illustrates a functional block diagram of an example of controlcircuitry 400 to control the exemplary embodiment of FIG. 3 . Thecontrol circuitry 400 includes a memory 402, an A/D converter 404,control latch 406, WDT 408, valve control 410, cooler power supply 412,cell power supply 414 and pump control and power supply 416communicating via a bus 420. The circuitry 400 is coupled, asillustrated to the reservoirs 306, 308 (i.e. to the sensors 340, 342,344), to the cooler 350, and the cell 200. The control circuitry 400 iscontrolled by a controller 430 coupled via the bus 420.

FIG. 5 shows a block diagram of an example embodiment of a machine inthe form of a computer system 500 within which a set of instructions maybe executed causing the system to perform any one or more of themethods, processes, operations, or methodologies discussed herein. Thecontroller 430, for example, may include the functionality of the one ormore computer systems 500.

The description of FIG. 5 is intended to provide a brief, generaldescription of suitable computer hardware and a suitable computingenvironment in conjunction with which aspects of the invention may beimplemented. In some embodiments, aspects of the inventive subjectmatter is described in the general context of computer-executableinstructions being executed by a computer.

Those skilled in the art will appreciate that the aspects of thedisclosure may be practiced with other computer system configurations,including hand-held devices, multiprocessor systems,microprocessor-based or programmable consumer electronics, smart phones,network PCs, minicomputers, mainframe computers, and the like. Aspectsof the disclosure may also be practiced in distributed computerenvironments where tasks are performed by I/O remote processing devicesthat are linked through a communications network. In a distributedcomputing environment, program modules may be located in both local andremote memory storage devices.

In an example embodiment, the machine operates as a standalone device ormay be connected (e.g., networked) to other machines. In a networkeddeployment, the machine may operate in the capacity of a server or aclient machine in server-client network environment, or as a peermachine in a peer-to-peer (or distributed) network environment. Themachine may be a server computer, a client computer, a personal computer(PC), a tablet PC, imbedded controller, a cellular telephone, a networkrouter, or any machine capable of executing a set of instructions(sequential or otherwise) that specify actions to be taken by thatmachine. Further, while only a single machine is illustrated, the term“machine” shall also be taken to include any collection of machines thatindividually or jointly execute a set (or multiple sets) of instructionsto perform any one or more of the methodologies discussed herein.

The example computer system 500 may include a processor 502 (e.g., acentral processing unit (CPU), a graphics processing unit (GPU) orboth), a main memory 504 and a static memory 506, which communicate witheach other via a bus 508. The computer system 500 further includes avideo display unit 510 (e.g., a liquid crystal display (LCD) plasma, ora cathode ray tube (CRT)). The computer system 500 also includes analphanumeric input device 512 (e.g., a keyboard), a cursor controldevice 514 (e.g., a mouse), a drive unit 516, a signal generation device518 (e.g., a speaker) and a network interface device 520.

The disk drive unit 516 includes a computer-readable medium 522 on whichis stored one or more sets of instructions (e.g., software 524)embodying any one or more of the methodologies or functions describedherein. The software 524 may also reside, completely or at leastpartially, within the main memory 504 and/or within the processor 502during execution thereof by the computer system 500, the main memory 504and the processor 502 also constituting computer-readable media. Thesoftware 524 may further be transmitted or received over a network 526via the network interface device 520.

While the computer-readable medium 522 is shown in an example embodimentto be a single medium, the term “computer-readable medium” should betaken to include a single medium or multiple media (e.g., a centralizedor distributed database, and/or associated caches and servers) thatstore the one or more sets of instructions. The term “computer-readablemedium” shall also be taken to include any medium that is capable ofstoring or encoding a set of instructions for execution by the machineand that cause the machine to perform any one or more of themethodologies of the present invention. The term “computer-readablemedium” shall accordingly be taken to include, but not be limited to,transitory and non-transitory media. Examples of non-transitory mediainclude but are not limited to solid-state memories, optical media, andmagnetic media. In some embodiments, the computer-readable medium is anon-transitory computer-readable medium.

The term “based on” or using, as used herein, reflects an open-endedterm that can reflect others elements beyond those explicitly recited.

Certain systems, apparatus, applications or processes are describedherein as including a number of modules. A module may be a unit ofdistinct functionality that may be presented in software, hardware, orcombinations thereof. When the functionality of a module is performed inany part through software, the module includes a computer-readablemedium. The modules may be regarded as being communicatively coupled.

The inventive subject matter may be represented in a variety ofdifferent embodiments of which there are many possible permutations.Although embodiments of the present invention have been described withreference to specific example embodiments, it will be evident thatvarious modifications and changes may be made to these embodimentswithout departing from the broader spirit and scope of the embodimentsof the invention. Accordingly, the specification and drawings are to beregarded in an illustrative rather than a restrictive sense.

Such embodiments of the inventive subject matter may be referred toherein, individually or collectively, by the term “invention” merely forconvenience and without intending to voluntarily limit the scope of thisapplication to any single invention or inventive concept if more thanone is, in fact, disclosed.

As is evident from the foregoing description, certain aspects of theinventive subject matter are not limited by the particular details ofthe examples illustrated herein, and it is therefore contemplated thatother modifications and applications, or equivalents thereof, will occurto those skilled in the art. It is accordingly intended that the claimsshall cover all such modifications and applications that do not departfrom the spirit and scope of the inventive subject matter. Therefore, itis manifestly intended that this inventive subject matter be limitedonly by the following claims and equivalents thereof.

The methods described herein do not have to be executed in the orderdescribed, or in any particular order. Moreover, various activitiesdescribed with respect to the methods identified herein can be executedin serial or parallel fashion.

The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quicklyascertain the nature of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims. In addition, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as reflecting anintention that the claimed embodiments require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter may lie in less than all features of asingle disclosed embodiment. Thus, the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separate embodiment.

The invention claimed is:
 1. A cell system for ozonation of watercomprising: a cathode having a gold surface and an anode, separated by apolymer membrane, the anode and cathode each have an array of holes toallow water to flow through to the membrane; a housing enclosing thecell and having a cathode housing portion and an anode housing portionseparated by the membrane, the cathode housing portion configured toallow water to flow across the cathode and the anode housing portionconfigured to allow water to flow across the anode, each housing portionhaving ridges arranged to direct water flow evenly over the cathode andthe anode; and input and output housing to allow water to flowseparately through both portions of the housing.
 2. The cell of claim 1wherein the membrane is a nafion membrane.
 3. The cell of claim 2further comprising a first O-ring between the cathode housing portionand the cathode, and a second O-ring between the anode housing portionand the anode.
 4. The cell of claim 1 wherein the anode is made ofniobium.
 5. The cell of claim 4 wherein the anode is plated on at leastone side with a diamond layer.
 6. The cell of claim 1 wherein the inputports are configured to be coupled to a pump to pump water through thehousing and over the cathode and anode.
 7. The cell of claim 3 whereinthe cathode housing portion further comprises a groove for receiving thefirst O-ring and the anode housing portion further comprising a groovefor receiving the second O-ring.
 8. The cell of claim 5 wherein thediamond layer is doped with boron.
 9. The cell of claim 1 wherein thecathode is made of stainless steel plated with gold.
 10. The cell ofclaim 1 wherein the array of holes covers at least 75 percent of eachelectrode's surface area exposed to the fluid.
 11. The cell of claim 1wherein the anode is composed of a niobium electrode having a texturedsurface which is coated with a diamond layer.
 12. The cell of claim 1wherein the anode is a thin niobium mesh coated with a layer of dopeddiamond.
 13. The cell of claim 1 wherein the housing maintains alignmentbetween the anode and the cathode.
 14. The cell of claim 1 furthercomprising an integrated spectral photometer including a bubble trap tomeasure ozone concentration.